Arthroscopic devices and methods

ABSTRACT

A tissue cutting probe includes an outer sleeve assembly, an inner sleeve assembly, a burr and an electrode. Each of the inner and outer sleeves has a proximal end, a distal end, and central passage extending therebetween. The inner sleeve assembly is coaxially and rotatably received in the central passage of the outer sleeve assembly, and the burr has a plurality of metal cutting edges carried on a first side of the distal end of the inner sleeve assembly. The electrode is carried a second side of the distal end of the inner sleeve assembly.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of U.S. Provisional No. 62/950,381(Attorney Docket No. 41879-751.101), filed Dec. 19, 2019, the entirecontent of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION 1. Field of the Invention

This invention relates to a medical system that includes variations ofmotor-driven tubular cutter or arthroscopic shavers that are configuredfor both mechanical cutting and electrosurgical cutting, ablation andcoagulation procedures.

2. Description of the Background Art

In endoscopic and other surgical procedures including subacromialdecompression, anterior cruciate ligament reconstruction involvingnotchplasty, and arthroscopic resection of the acromioclavicular joint,there is a need for cutting and removal of bone and soft tissue.Currently, surgeons use arthroscopic shavers and burrs having rotationalcutting surfaces to remove hard tissue in such procedures.

To promote efficiency, endoscopic tool systems including a reusablehandpiece and a selection of interchangeable tool probes havingdifferent working ends have been proposed. Such working ends may eachhave two or more functionalities, such as soft tissue removal and hardtissue resection, so such tools systems can provide dozens of specificfunctionalities, providing great flexibility.

While a significant advantage, the need for one tool system toaccommodate such flexibility is a challenge. In particular, it isnecessary that the handpiece and control unit for the system be providedwith correct information on the identity of the tool probe that has beenattached as well as the operational parameters of the tool probe duringuse.

It is therefore an object of the present invention to provide improvedsurgical systems and methods for their use, such as improvedarthroscopic tissue cutting and removal system wherein a motor-drivenelectrosurgical device is provided for cutting and removing bone or softtissue from a joint or other site. It is a further object invention toprovide improved systems and methods for device identification,monitoring, and control, such as controlled operational stopping andstarting of motor-driven components in default positions. At least someof these objectives will be met by the inventions described herein.

SUMMARY OF THE INVENTION

In a first aspect, the present invention provides a tissue cutting probecomprising an outer sleeve assembly and an inner sleeve assembly. Boththe outer sleeve assembly and the inner sleeve assembly have a proximalend, a distal end, and central passage extending therebetween, and theinner sleeve assembly is coaxially and rotatably received in the centralpassage of the outer sleeve assembly. A burr having a plurality of metalcutting edges is carried on or comprises a first side of the distal endof the inner sleeve assembly, and an electrode is carried or comprises asecond side of the distal end of the inner sleeve assembly. Such probesare may be used in a variety of tissue cutting, tissue ablation, tissuecoagulation and other surgical procedures but will find particular usein procedures involving the cutting of bone and other hard tissues withthe burr and the ablation and coagulation of soft tissues with theelectrode.

In some embodiments, the first side and the second side of the distalend on the inner sleeve assembly are on opposed surfaces of the innersleeve assembly. For example, the burr may be formed on or comprise ametal member that extends at least 180° circumferentially about thedistal end of the inner sleeve assembly, and/or the electrode may becarried on or comprise a dielectric body on the distal end of the innersleeve assembly.

In some embodiments, the probe may further comprise a scoop extendsdistally from the distal end of the outer sleeve assembly. For example,the scoop may be axially aligned with the burr and the electrode on theinner sleeve assembly so that the scoop will alternatively cover each ofthe burr and the electrode as the inner sleeve assembly is rotatedwithin the outer sleeve assembly.

In some embodiments, one or more aspiration ports may be formed in orthrough a wall of the outer sleeve assembly and/or one or more lateralopenings may be formed in a wall of the inner sleeve assembly. The oneor more aspiration ports are typically positioned to align with the oneor more lateral openings as the inner sleeve assembly is rotated withinthe outer sleeve assembly. That is, the aspiration port(s) and thelateral opening(s) will periodically and/or success successively fallinto and out of alignment. When aligned, a negative pressure appliedthrough the central passage of the inner sleeve assembly will be able todraw or suction tissue debris though the aligned openings to at leastpartially clear the surgical field, typically an arthroscopic or otherendoscopic field filled with saline or other fluid.

In a second aspect, the present invention provides a tissue cuttingsystem comprising a probe and a controller. The probe may comprise anelongated shaft, an active electrode, and a return electrode. Theelongated shaft comprises an inner sleeve assembly co-axially mounted torotate about a longitudinal axis within an outer sleeve assembly. Theinner sleeve assembly is rotatable at greater than 1000 RPM within outersleeve assembly. The active electrode and the return electrode disposedon a distal end of the inner sleeve assembly. The controller isconfigured to deliver radiofrequency (RF) current to the active andreturn electrodes and to limit RF current delivery when the activeelectrode is proximate the return electrode during rotation of the innersleeve assembly. Such a system allows the physician to deliver currentto the active and return electrodes as the inner sleeve assembly isbeing rotated at very high rates with reduced risk of shorting theactive and return electrodes as hey move in and out of proximity to eachother as the inner sleeve assembly rotates.

In some embodiments of the systems of the present invention, thecontroller is configured to sense current or voltage flowing to theactive electrode and compare a sensed value to a reference value. Thecurrent flow can be disabled when the sensed value exceeds the referencevalue, thus inhibiting or prevent shorting between the active and returnelectrodes. Typically, current flow may be enabled when the sensed valuefalls below the reference value. For example, the current flow may beenabled or disabled each time the reference value is exceeded or fallsbelow by a threshold value to prevent oscillation.

In a third aspect, the present invention provides method for cuttingtissue comprising engaging a distal end of a probe against a tissuetarget. A distal end of a sleeve assembly carries a burr having aplurality of metal cutting edges on a first side thereof and anelectrode on a second side thereof. The sleeve assembly may be rotatedto successively engage the burr and the electrode against the targettissue, typically comprising both hard tissue such as bone and softtissue. A radiofrequency (RF) current may be selectively applying to theelectrode and a return electrode as the sleeve assembly is rotated,where current flow is enable when the electrode is remote from thereturn electrode and current flow is disabled when the electrode isproximate the return electrode as the sleeve assembly is rotated, thusreducing or eliminating the risk of shorting.

In some embodiments of the methods of the present invention, rotatingmay comprise rotating at a speed of at least 1000 RPM.

In some embodiments of the methods of the present invention, selectivelyapplying current may comprises sensing a current or voltage flowing tothe active electrode and comparing a sensed value to a reference value,wherein the current flow is disabled when the sensed value exceeds thereference value. For example, the current flow may be enabled when thesensed value falls below the reference value, e.g. the current flow maybe enabled or disabled when the reference value is exceeded or fallenbelow by a threshold value to prevent oscillation.

In some embodiments of the methods of the present invention, the activeelectrode may be on an inner sleeve and the return electrode may be onan outer sleeve, where the inner sleeve is rotated within the outersleeve.

In some embodiments, the methods of the present invention may furthercomprise drawing a negative pressure on the probe to aspirate cuttingdebris as the sleeve assembly is rotated.

In some embodiments of the methods of the present invention, the firstside and the second side may be on opposed surfaces of the inner sleeveassembly. For example, the burr may be formed on a metal member thatextends at least 180° circumferentially about the distal end of theinner sleeve assembly and/or the electrode may be carried on adielectric body on the distal end of the inner sleeve assembly.

In some embodiments of the methods of the present invention, a scoop mayextend distally from the distal end of the outer sleeve assembly. Forexample, the scoop may be axially aligned with the burr and theelectrode on the inner sleeve assembly so that the scoop willalternatively cover each of the burr and the electrode as the innersleeve assembly is rotated within the outer sleeve assembly.

In alternative aspects, present invention provides improved apparatusand methods for identifying and controlling working components, such asmotor-driven and other powered components, of surgical systems,particularly for arthroscopic and other surgical systems including (1)handpieces having motor drive units and (2) probes which are selectivelyand removably attached to the handpieces. In exemplary embodiments, thepresent invention provides methods and systems which rely on magnets andmagnetic sensors for providing information to system controllers both ina static mode, where a laparoscopic or other tool is not being driven,and in a dynamic mode, where the tool is being driven by the motordrive. In particular embodiments, the magnets are permanent magnetshaving North poles and South poles, where the magnets are typicallymounted on or otherwise attached or coupled to components of adetachable probe forming part of an arthroscopic system, and the sensorsare Hall sensors which are in the handpiece of the arthroscopic system.By using multiple magnets and multiple sensors, different types ofinformation can be provided to the system controller, such asidentification of the tool in the detachable probe, operatingcharacteristics of the probe, system calibration information, and thelike. While the exemplary embodiments of present invention typicallyrely on magnetic sensors, static and dynamic data acquisition from thetool probe to the associated controller and be accomplished with othersensors as well, such as optical sensors which are able to readinformation in both a static mode and in a dynamic mode.

In a first alternative aspect of the present invention, an arthroscopicsystem comprises a handpiece and a probe. The handpiece includes a motordrive, and the probe has a proximal hub and an elongate shaft whichextends about a longitudinal axis to a working end of the probe. The hubis configured for detachably coupling to the handpiece, and the motordrive is configured to couple to a rotating drive coupling in the hubwhen the hub is coupled to the handpiece. A first magnetic component iscarried by the hub, and a second magnetic component is coupled to rotatewith the rotating drive coupling.

In specific alternative aspects, the hub may be configured fordetachable coupling to the handpiece in opposing rotationalorientations, such as an orientation where a working end of the probe isfacing upwardly and a second orientation where the working end of theprobe is facing downwardly relative to the handpiece. In suchembodiments, the first magnetic component may comprise first and secondindependent magnets, typically permanent magnets have North poles andSouth poles, disposed in or on opposing sides of the hub and spacedoutwardly from the longitudinal axis. The first and second independentmagnets of the first magnetic component will typically have a “polarorientation,” for example the North poles will be oriented in oppositedirections relative to said axis. Typically, though not necessarily, thefirst and second independent magnets may have similar magnetic fieldstrengths. In such embodiments, the handpiece may further comprise afirst sensor configured for “statically” sensing a magnetic field of thefirst or second independent magnets when located adjacent the firstsensor. By “statically” sensing, it is meant that the magnets do notneed to be moving relative to the sensor. The sensor will thus be ableto generate a signal indicating whether the working end is in itsupward-facing orientation or its downward-facing orientation. The firstsensor may be further configured for generating a probe identificationsignal based on the magnetic field strength (or other magneticcharacteristic) which correlates a probe type with different magneticfield strengths, typically by using a look-up table maintained in anassociated controller.

In still alternative embodiments, the second magnetic componentcomprises third and fourth independent magnets disposed in or onopposing sides of the rotating drive coupling. The third and fourthindependent magnets of the second magnetic component will typically haveNorth poles in opposing orientations relative to said axis, usually in amanner similar to the first and second independent magnets. Thehandpiece will further comprise a second sensor configured for sensing amagnetic field of the third or fourth independent magnets as the magnetcomes into proximity to the second sensor. In this way, the secondsensor can dynamically sense and generate a signal indicating arotational parameter of the rotating drive coupling. For example, therotational parameter may comprise a rotational position of the drivecoupling. Alternatively or additionally, the rotational parameter maycomprise a rotational speed of the drive coupling based on therotational positioning over a time interval.

These arthroscopic and other surgical systems may be further configuredfor determining orientation of the motor-driven component so that theworking end can be stopped in a desired position. For example, thesecond magnetic component carried by the drive coupling may be in afixed predetermined rotational relationship to a motor-driven componentin the working end. In this way, a rotational positioning of thecomponent in the working end van be controlled based on the rotationalposition of the drive coupling.

Such systems of the present invention may further comprise a controllerconfigured to receive the signals generated by the sensors and providemonitoring and control of the endoscopic or other surgical tool based onthe received signals. For example, by receiving signals generated by thefirst sensor within the hub, at least one of probe-orientation and probeidentification can be determined. Similarly, by receiving signalsgenerated by the second sensor within the hub, the controller may beconfigured to monitor and/or control the motor speed and otheroperational characteristics.

In a second alternative aspect of the present invention, a method forperforming an arthroscopic procedure comprises providing a systemincluding a handpiece with a sensor. The system further comprises aprobe having a proximal hub, a longitudinal axis, and a working end. Thehub typically carries first and second magnets having North and Southpoles. The hub is selectively coupled to the handpiece with the workingend of the probe in either an upward orientation or a downwardorientation. The first magnet is located proximately to sensor when theworking end is in the upward orientation, and the second magnet islocated proximately to sensor when the working end is in the downorientation. In this way, an upward orientation or a downwardorientation of the working end can be determined based on whether aNorth pole or a South pole of the magnet is proximate to the sensor.Such orientational information is used for a variety of purposes,including selecting a controller algorithm for operating the probe basedon the identified orientation of the working end.

In a third alternative aspect of the present invention, an arthroscopicor other surgical method comprises providing a system including ahandpiece with a sensor. The system further comprises a probe with aproximal hub, a longitudinal axis, and a working end. The hub will carryfirst and second magnets of similar strengths and having North and Southpoles. The hub is coupled to the handpiece, and a magnetic strength ofeither (or both) of the magnets is sensed using a sensor in thehandpiece to identify the probe type based on the sensed magneticstrength. Identification of the probe type is useful for a variety ofpurposes, including allowing selection of a control algorithm (to beused by a controller coupled to probe and sensors) to control theworking end of the tool based on the identified probe type.

In a fourth alternative aspect, an arthroscopic or other surgicalprocedure comprises providing a system including a handpiece with amotor drive. The system further comprises a probe having a proximal hub,a longitudinal axis, a rotating drive coupling, and a working end. Therotating drive coupling typically carries first and second magnetshaving North and South poles where each pole is positioned in adifferent orientation relative to the axis. The hub is attached to thehandpiece to couple the motor drive to the rotating drive coupling inthe hub. The rotating drive coupling actuates a motor-driven or othercomponent in the working end, e.g. the motor drive may be activated torotate the drive coupling and actuate the motor-driven component. Avarying magnetic parameter is sensed with a sensor in the handpiece asthe drive coupling rotates in order to generate sensor signals. Arotational position of the drive coupling can thus be determined, andthe corresponding positions of the motor-driven component calculatedusing a positioning algorithm responsive to the sensor signals. Themotor drive can be selectively deactivated at a desired rotationalposition based on the positional information which has been thusdetermined. After deactivating the motor drive, the system candynamically brake the motor drive to thereby stop rotation of the drivecoupling and stop movement of the motor-driven component in a selectivestop position in a highly accurate manner.

In a fifth alternative aspect of the present invention, an arthroscopicprocedure comprises providing a system including a handpiece with amotor drive. The system further comprises a probe with a proximal huband an elongate shaft extending about an axis to a working end. The hubis configured for detachable coupling to the handpiece, and the motordrive is configured to couple to a rotating drive coupling in the hub.The drive coupling, in turn, carries first and second magnets with Northand South poles positioned in different orientations relative to theaxis. The hub is coupled to the handpiece, and the motor drive isactivated to rotate the drive coupling and magnets through an arc of atleast 180°. A varying strength of each magnet is then sensed with asensor in the handpiece as the drive coupling rotates. A rotationalposition of the drive coupling responsive to the varying strength ofeach magnet can be calibrated in order to increase accuracy insubsequent calculation of the sensed strengths of the magnets.

In a sixth alternative aspect of the present invention, an arthroscopicprocedure comprises providing a handpiece with a motor drive. The systemfurther comprises a probe having a proximal hub and an elongate shaftextending about a longitudinal axis to a working end having amotor-driven component. The motor-driven component includes a radiofrequency (RF) electrode, and a hub is configured for detachablecoupling to the handpiece. The motor drive is configured to couple to arotating drive in the coupling of the hub, and the rotating drivecoupling is configured to carry first and second magnets with North andSouth poles positioned in different orientations relative to the axis.The hub is coupled to the handpiece, and the drive coupling andmotor-driven component are positioned in a selected stop position. TheRF electrode is typically exposed in the selected stop position and canbe introduced to a target site to engage or interface with tissue. RFcurrent is then delivered to the RF electrode, and a positioningalgorithm responsive to sensor signals continuously monitors therotational position of the drive coupling and the corresponding positionof the motor-driven component and the RF electrode while RF current isbeing delivered. Such position monitoring is useful because it allowsthe positioning algorithm to sense a rotation or rotational deviationgreater than a predetermined amount, in which case the delivery of RFcurrent to the RF electrode can be terminated. Additionally oralternatively, the positioning algorithm can further activate or adjustthe motor drive to return the RF electrode back to a selected or desiredstop position.

In a seventh alternative aspect, an arthroscopic procedure comprisesproviding a handpiece with a motor drive and a probe with a proximalhub. An elongate shaft of the hub extends about an axis to a workingend, and a motor driven component in the working end includes an RFelectrode. The hub is configured for detachably coupling to thehandpiece, and the motor drive is configured to couple to a rotatingdrive coupling in the hub. The rotating drive carries first and secondmagnets with North and South poles having different orientationsrelative to the axis. The hub is coupled to the handpiece, and the drivecoupling and motor-driven component may be positioned in a selected stopposition. The RF electrode may be engaged against a target issue surfaceor interface, and an RF current may be delivered to the RF electrode.Using a positioning algorithm responsive to sensor signals indicating arotational position of the drive coupling, the RF electrode can beoscillated in the range from 20 Hz to 2000 Hz. Often, oscillation of theRF electrode at a rate ranging from 40 Hz to 400 Hz.

In an eighth alternative aspect, the present invention comprises amethod for providing information from a surgical probe to a controller.A hub of the probe is attached to a handpiece connected to thecontroller. The hub carries indicia, and a first set of data obtainedfrom reading the first set of indicia on the hub may be read using afirst sensor on the handpiece, where the first set of data can then besent to the controller. A second set of indicia on the hub is also readusing a second sensor on the handpiece, and a second set of dataobtained from the second reading may also be sent to the controller. Thefirst set of data includes at least one of probe identificationinformation and probe orientation information, and the second set ofdata includes at least probe operational information.

In alternative embodiments, the first and/or second set of indicia maycomprise magnets, as taught in any of previously described embodiments.In alternative embodiments, however, the first and/or second sets ofindicia may comprise optical encoding or any other type of data encodingthat can be read using sensors in the handpiece. For example, the firstset of indicia may comprise optical encoding including a scannable codeon a stationary component of the hub, such as a housing. The first setof indicia incorporates said at least one of probe identificationinformation and probe orientation information and can be read when thecode is static relative to the handpiece, typically using a stationaryoptical scanner, such as a bar or 3D code reader. In other examples, thesecond set of indicia may comprise optical encoding configured to beread by a scannable code reader, e.g., markings on a rotatable componentof the hub, wherein at least the probe operational information isconfigured to read from the markings as the rotatable componentdynamically rotates. For example, the markings may be read by an opticalcounter that can determine a rotation speed, such as revolutions perminute (RPM).

BRIEF DESCRIPTION OF THE DRAWINGS

Various embodiments of the present invention will now be discussed withreference to the appended drawings. It should be appreciated that thedrawings depict only typical embodiments of the invention and aretherefore not to be considered limiting in scope.

FIG. 1 is a perspective view of an arthroscopic cutting system thatincludes reusable handpiece with a motor drive and a detachablesingle-use cutting probe, wherein the cutting probe is shown in twoorientations as it may be coupled to the handpiece with the probe andworking end in upward orientation or a downward orientation relative tothe handpiece, and wherein the handpiece includes an LCD screen fordisplaying operating parameters of system during use together withcontrol actuators on the handpiece.

FIG. 2A is an enlarged longitudinal sectional view of the hub of theprobe of FIG. 1 taken along line 2A-2A of FIG. 1 with the hub and probein an upward orientation relative to the handpiece, further showing Halleffect sensors carried by the handpiece and a plurality of magnetscarried by the probe hub for device identification, for probeorientation and determining the position of motor driven components ofthe probe relative to the handpiece.

FIG. 2B is a sectional view of the hub of FIG. 1 taken along line 2B-2Bof FIG. 1 with the hub and probe in a downward orientation relative tothe handpiece showing the Hall effect sensor and magnets having adifferent orientation compared to that of FIG. 2A.

FIG. 3A is an enlarged perspective view of the working end of the probeof FIG. 1 in an upward orientation with the rotatable cutting member ina first position relative to the outer sleeve wherein the window in thecutting member is aligned with the window of the outer sleeve.

FIG. 3B is a perspective view of the working end of FIG. 1 in an upwardorientation with the rotatable cutting member in a second positionrelative to the outer sleeve wherein the electrode carried by thecutting member is aligned with a centerline of the window of the outersleeve.

FIG. 4 is a perspective view of a working end of a variation of a probethat may be detachably coupled to the handpiece of FIG. 1 , wherein theworking end includes a bone burr extending distally from the outersleeve.

FIG. 5 is a perspective view of a working end of a variation of a probethat may be detachably coupled to the handpiece of FIG. 1 , wherein theworking end has a reciprocating electrode.

FIG. 6 is a perspective view of a working end of another variation of aprobe that may be detachably coupled to the handpiece of FIG. 1 ,wherein the working end has a hook electrode that has extended andnon-extended positions.

FIG. 7 is a perspective view of a working end of yet another variationof a probe that may be detachably coupled to the handpiece of FIG. 1 ,wherein the working end has an openable-closeable jaw structure forcutting tissue.

FIG. 8 is a chart relating to set speeds for a probe with a rotatingcutting member as in FIGS. 1 and 3A that schematically shows the methodused by a controller algorithm for stopping rotation of the cuttingmember in a selected default position.

FIG. 9A is a longitudinal sectional view of a probe hub that is similarto that of FIG. 2A, except the hub of FIG. 9A has an internal cammechanism for converting rotational motion to linear motion to axiallyreciprocate an electrode as in the working end of FIG. 5 , wherein FIG.9A illustrated the magnets in the hub and drive coupling are the same asin FIG. 2A and the hub is in an upward facing position relative to thehandpiece.

FIG. 9B is a sectional view of the hub of FIG. 9A rotated 180° in adownward facing position relative to the handpiece.

FIG. 10 is a perspective view of another variation of a probe that showsa motor-driven, rotating inner cutting sleeve that includes alongitudinal dielectric member coupled to a longitudinal conductivemetal portion, wherein the dielectric member carries an active electrodeand the longitudinal conductive metal portion comprises a returnelectrode.

FIG. 11 is an enlarged perspective view of the working end of FIG. 10with the inner sleeve separated from the outer sleeve.

FIG. 12 is a perspective view of the working end as in FIG. 11 with theinner sleeve rotated 180°.

FIG. 13 is a perspective view of the working end of the probe of FIG. 10in an exploded view showing the components thereof.

FIG. 14 is a perspective exploded view of the working end as in FIG. 13rotated 180° to show another side of the components thereof.

FIG. 15 is a perspective and partly assembled view of the working end ofFIGS. 10-14 showing electrical connections therein.

FIG. 16A is an end view of components of the working end of FIGS. 10-15.

FIG. 16B is a cross-sectional view of components of the working end ofFIGS. 10-15 taken along line 16B-16B of FIG. 13 .

FIG. 17 is a perspective view of the working end of FIGS. 10-15 showingRF current paths between active and return electrodes.

FIG. 18 is a perspective exploded view of a working end of anothervariation of a probe similar to that of FIG. 10 showing the componentsthereof.

FIG. 19 is an end view of components of the working end of FIG. 18 .

FIG. 20 is a perspective exploded view of another variation of a probesimilar to that of FIGS. 10 and 18 showing the components thereof.

FIG. 21 is an end view of components of the working end of FIG. 20 .

FIG. 22 is a perspective partly disassembled view of another variationof a probe similar to that of FIGS. 10 and 18 showing the componentsthereof.

FIG. 23 is another perspective view of components of the working end ofFIG. 22 .

FIG. 24 is an exploded view of the component of the probe of FIGS. 22and 23 .

FIG. 25A is a perspective view of the probe of FIGS. 22 and 23 showingthe hub and shaft of the probe.

FIG. 25B is a longitudinal sectional view of the probe of FIG. 25A.

FIG. 26 is an enlarged sectional view of a portion of the hub of theprobe of FIG. 25B.

FIG. 27 is a perspective view of another variation of a probe somewhatsimilar to that of FIG. 10 but having a burr configuration for cuttinghard tissue such as bone.

FIG. 28 is an enlarged perspective view of the working end of the probeof FIG. 27 with the inner sleeve assembly and burr separated from theouter sleeve.

FIG. 29 is a perspective view of inner sleeve assembly of the probe ofFIGS. 27-28 with bushing removed to show an electrical connections and astructural retaining collar.

FIG. 30 is a longitudinal sectional view of the distal portion of theinner sleeve assembly of the probe of FIGS. 27-28 .

FIG. 31 is a perspective view of the working end of the probe of FIG. 27in an exploded view showing the components thereof.

FIG. 32 is a schematic view of the electrical circuitry of the inventionadapted for instantaneous ON/OFF delivery of RF current to an activeelectrode during 360° rotation of the inner sleeve assembly.

FIG. 33 is a schematic view of another aspect of the circuitry of FIG.32 .

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to bone cutting and tissue removal devicesand related methods of use. Several variations of the invention will nowbe described to provide an overall understanding of the principles ofthe form, function and methods of use of the devices disclosed herein.In general, the present disclosure provides for variations ofarthroscopic tools adapted for cutting bone, soft tissue, meniscaltissue, and for RF ablation and coagulation. The arthroscopic tools aretypically disposable and are configured for detachable coupling to anon-disposable handpiece that carries a motor drive component. Thisdescription of the general principles of this invention is not meant tolimit the inventive concepts in the appended claims.

In one variation shown in FIG. 1 , the arthroscopic system 100 of thepresent invention provides a handpiece 104 with motor drive 105 and adisposable shaver assembly or probe 110 with a proximal hub 120 that canbe received by receiver or bore 122 in the handpiece 104. In one aspect,the probe 110 has a working end 112 that carries a high-speed rotatingcutter that is configured for use in many arthroscopic surgicalapplications, including but not limited to treating bone in shoulders,knees, hips, wrists, ankles and the spine.

In FIGS. 1, 2A and 3A, it can be seen that probe 110 has a shaft 125extending along longitudinal axis 128 that comprises an outer sleeve 140and an inner sleeve 142 rotatably disposed therein with the inner sleeve142 carrying a distal ceramic cutting member 145 (FIG. 3A). The shaft125 extends from the proximal hub 120 wherein the outer sleeve 140 iscoupled in a fixed manner to the hub 120 which can be an injectionmolded plastic, for example, with the outer sleeve 140 insert moldedtherein. The inner sleeve 142 is coupled drive coupling 150 that isconfigured for coupling to the rotating motor shaft 151 of motor driveunit 105. More in particular, the rotatable cutting member 145 that isfabricated of a ceramic material with sharp cutting edges on opposingsides 152 a and 152 b of window 154 therein for cutting soft tissue. Themotor drive 105 is operatively coupled to the ceramic cutter to rotatethe cutting member at speeds ranging from 1,000 rpm to 20,000 rpm. InFIG. 3B, it can be seen that cutting member 145 also carries an RFelectrode 155 in a surface opposing the window 154. The cutting member145 rotates and shears tissue in the toothed opening or window 158 inthe outer sleeve 140 (FIG. 3A). A probe of the type shown in FIG. 1 isdescribed in more detail in co-pending and commonly owned patentapplication Ser. No. 15/421,264 filed Jan. 31, 2017 (Atty. Docket41879-714.201) titled ARTHROSCOPIC DEVICES AND METHODS which isincorporated herein in its entirety by this reference.

As can be seen in FIG. 1 , the probe 110 is shown in two orientationsfor detachable coupling to the handpiece 104. More particularly, the hub120 can be coupled to the handpiece 104 in an upward orientationindicated at UP and a downward orientation indicated at DN where theorientations are 180° opposed from one another. It can be understoodthat the upward and downward orientations are necessary to orient theworking end 112 either upward or downward relative to the handpiece 104to allow the physician to interface the cutting member 145 with targetedtissue in all directions without having to manipulate the handpiece in360° to access tissue.

In FIG. 1 , it can be seen that the handle 104 is operatively coupled byelectrical cable 160 to a controller 165 which controls the motor driveunit 105 Actuator buttons 166 a, 166 b or 166 c on the handle 104 can beused to select operating modes, such as various rotational modes for theceramic cutting member 145. In one variation, a joystick 168 can bemoved forward and backward to adjust the rotational speed of the ceramiccutting member 145. The rotational speed of the cutter can continuouslyadjustable, or can be adjusted in increments up to 20,000 rpm. An LCDscreen 170 is provided in the handpiece for displaying operatingparameters, such as cutting member RPM, mode of operation, etc.

It can be understood from FIG. 1 that the system 100 and handpiece 104is adapted for use with various disposable probes which can be designedfor various different functions and procedures. For example, FIG. 4illustrates a different variation of a probe working end 200A that issimilar to working end 112 of probe 110 of FIGS. 3A-3B, except theceramic cutting member 205 extends distally from the outer sleeve 206and the cutting member has burr edges 208 for cutting bone. The probe ofFIG. 4 is described in more detail in co-pending and commonly ownedpatent application Ser. No. 15/271,184 filed Sep. 20, 2016 (Atty. Docket41879-728.201) titled ARTHROSCOPIC DEVICES AND METHODS. FIG. 5illustrates a different variation of a probe working end 200B with areciprocating electrode 210 in a type of probe described in more detailin co-pending and commonly owned patent application Ser. No. 15/410,723filed Jan. 19, 2017 (Atty. Docket 41879-713.201) titled ARTHROSCOPICDEVICES AND METHODS. In another example, FIG. 6 illustrates anothervariation of a probe working end 200C that has an extendable-retractablehook electrode 212 in a probe type described in more detail inco-pending and commonly owned patent application Ser. No. 15/454,342filed Mar. 9, 2017 (Atty. Docket 41879-715.201) titled ARTHROSCOPICDEVICES AND METHODS. In yet another example, FIG. 7 illustrates avariation of a working end 200D in a probe type having anopenable-closable jaw structure 215 actuated by reciprocating member 218for trimming meniscal tissue or other tissue as described in more detailin co-pending and commonly owned patent application Ser. No. 15/483,940filed Apr. 10, 2017 (Atty. Docket 41879-721.201) titled ARTHROSCOPICDEVICES AND METHODS. All of the probes of FIGS. 4-7 can have a hubsimilar to hub 120 of probe 110 of FIG. 1 for coupling to the samehandpiece 104 of FIG. 1 , with some of the probes (see FIGS. 5-7 )having a hub mechanism for converting rotational motion to linearmotion. All of the patent applications just identified in this paragraphare incorporated herein by this reference.

FIG. 1 further shows that the system 100 also includes a negativepressure source 220 coupled to aspiration tubing 222 which communicateswith a flow channel 224 in handpiece 104 and can cooperate with any ofthe probes 110, 200A, 200B or 200C of FIGS. 1-3B, 4, 5 and 6 . In FIG. 1it also can be seen that the system 100 includes an RF source 225 whichcan be connected to an electrode arrangement in any of the probes 110,200A, 200B or 200C of FIGS. 1-3B, 4, 5 and 6 . The controller 165 andmicroprocessor therein together with control algorithms are provided tooperate and control all functionality, which includes controlling themotor drive 105 to move a motor-driven component of any probe workingend 110, 200A, 200B or 200C, as well as for controlling the RF source225 and the negative pressure source 220 which can aspirate fluid andtissue debris to collection reservoir 230.

As can be understood from the above description of the system 100 andhandpiece 104, the controller 165 and controller algorithms need to beconfigured to perform and automate many tasks to provide for systemfunctionality. In a first aspect, controller algorithms are needed fordevice identification so that when any of the different probes types110, 200A, 200B, 200C or 200D of FIGS. 1 and 4-7 are coupled tohandpiece 104, the controller 165 will recognize the probe type and thenselect algorithms for operating the motor drive 105, RF source 225 andnegative pressure source 220 as is needed for the particular probe. In asecond aspect, the controller is configured with algorithms thatidentify whether the probe is coupled to the handpiece 104 in an upwardor downward orientation relative to the handpiece, wherein eachorientation requires a different subset of the operating algorithms. Inanother aspect, the controller has separate control algorithms for eachprobe type wherein some probes have a rotatable cutter while others havea reciprocating electrode or jaw structure. In another aspect, most ifnot all the probes 110, 200A, 200B, 200C and 200D (FIGS. 1, 4-7 )require a default “stop” position in which the motor-driven component isstopped in a particular orientation within the working end. For example,a rotatable cutter 145 with an electrode 155 needs to have the electrodecentered within an outer sleeve window 158 in a default position such asdepicted in FIG. 3B. Some of these systems, algorithms and methods ofuse are described next.

Referring to FIGS. 1 and 2A-2B, it can be seen that handpiece 104carries a first Hall effect sensor 240 in a distal region of thehandpiece 104 adjacent the receiving passageway 122 that receives thehub 120 of probe 110. FIG. 2A corresponds to the probe 110 and workingend 112 in FIG. 1 being in the upward orientation indicated at UP. FIG.2B corresponds to probe 110 and working end 112 in FIG. 1 being in thedownward orientation indicated at DN. The handpiece 104 carries a secondHall effect sensor 245 adjacent the rotatable drive coupling 150 of theprobe 110. The probe 110 carries a plurality of magnets as will bedescribed below that interact with the Hall effect sensors 240, 245 toprovide multiple control functions in cooperation with controlleralgorithms, including (i) identification of the type of probe coupled tothe handpiece, (ii) the upward or downward orientation of the probe hub120 relative to the handpiece 104, and (iii) the rotational position andspeed of rotating drive collar 150 from which a position of eitherrotating or reciprocating motor-driven components can be determined.

The sectional views of FIGS. 2A-2B show that hub 120 of probe 110carries first and second magnets 250 a and 250 b in a surface portionthereof. The Hall sensor 240 in handpiece 104 is in axial alignment witheither magnet 250 a or 250 b when the probe hub 120 is coupled tohandpiece 104 in an upward orientation (FIGS. 1 and 2A) or a downwardorientation (FIGS. 1 and 2B). In one aspect as outlined above, thecombination of the magnets 250 a and 250 b and the Hall sensor 240 canbe used to identify the probe type. For example, a product portfolio mayhave from 2 to 10 or more types of probes, such as depicted in FIGS. 1and 4-7 , and each such probe type can carry magnets 250 a, 250 b havinga specific, different magnetic field strength. Then, the Hall sensor 240and controller algorithms can be adapted to read the magnetic fieldstrength of the particular magnet(s) in the probe which can be comparedto a library of field strengths that correspond to particular probetypes. Then, a Hall identification signal can be generated or otherwiseprovided to the controller 165 to select the controller algorithms foroperating the identified probe, which can include parameters foroperating the motor drive 105, negative pressure source 220 and/or RFsource 225 as may be required for the probe type. As can be seen inFIGS. 1, 2A and 2B, the probe hub 120 can be coupled to handpiece 104 inupward and downward orientations, in which the North (N) and South (S)poles of the magnets 250 a, 250 b are reversed relative to the probeaxis 128. Therefore, the Hall sensor 240 and associated algorithms lookfor magnetic field strength regardless of polarity to identify the probetype.

Referring now to FIGS. 1, 2A-2B and 3A-3B, the first and second magnets250 a and 250 b with their different orientations of North (N) and South(S) poles relative to central longitudinal axis 128 of hub 120 are alsoused to identify the upward orientation UP or the downward orientationDN of hub 120 and working end 112. In use, as described above, thephysician may couple the probe 110 to the handpiece receiving passageway122 with the working end 112 facing upward or downward based on his orher preference and the targeted tissue. It can be understood thatcontroller algorithms adapted to stop rotation of the cutting member 145in the window 158 of the outer sleeve 104 of working end 112 need to“learn” whether the working end is facing upward or downward, becausethe orientation or the rotating cutting member 145 relative to thehandpiece and Hall sensor 240 would vary by 180°. The Hall sensor 240together with a controller algorithm can determine the orientation UP orthe downward orientation DN by sensing whether the North (N) or South(S) pole of either magnet 250 a or 250 b is facing upwardly and isproximate the Hall sensor 240.

In another aspect of the invention, in probe 110 (FIG. 1 ) and otherprobes, the motor-driven component of a working end, such as rotatingcutter 145 of working end 112 of FIGS. 1 and 3A-3B needs to stopped in aselected rotational position relative to a cut-out opening or window 158in the outer sleeve 140. Other probe types may have a reciprocatingmember or a jaw structure as described above, which also needs acontroller algorithm to stop movement of a moving component in aselected position, such as the axial-moving electrodes of FIGS. 5-6 andthe jaw structure of FIG. 7 . In all probes, the motor drive 105 couplesto the rotating drive coupling 150, thus sensing the rotational positionof the drive coupling 150 can be used to determine the orientation ofthe motor-driven component in the working end. More in particular,referring to FIGS. 1 and 2A-2B, the drive coupling 150 carries third andfourth magnets 255 a or 255 b with the North (N) and South (S) poles ofmagnets 255 a or 255 b being reversed relative to the probe axis 128.Thus, Hall sensor 245 can sense when each magnet rotates passes the Hallsensor and thereby determine the exact rotational position of the drivecoupling 150 twice on each rotation thereof (once for each magnet 255 a,255 b). Thereafter, a controller tachometer algorithm using a clock candetermine and optionally display the RPM of the drive coupling 150 and,for example, the cutting member 145 of FIG. 3A.

In another aspect of the invention, the Hall sensor 245 and magnets 255a and 255 b (FIGS. 1 and 2A) are used in a set of controller algorithmsto stop the rotation of a motor-driven component of a working end, forexample, cutting member 145 of FIGS. 1 and 3A-3B in a pre-selectedrotational position. In FIG. 3A, it can be seen that the inner sleeve142 and a “first side” of cutting member 145 and window 154 therein isstopped and positioned in the center of window 158 of outer sleeve 140.The stationary position of cutting member 145 and window 154 in FIG. 3Amay be used for irrigation or flushing of a working space to allow formaximum fluid outflow through the probe.

FIG. 3B depicts inner sleeve 142 and a “second side” of cutting member145 positioned about the centerline of window 158 in the outer sleeve140. The stationary or stopped position of cutting member 145 in FIG. 3Bis needed for using the RF electrode 155 to ablate or coagulate tissue.It is important that the electrode 155 is maintained along thecenterline of the outer sleeve window 158 since the outer sleeve 140typically comprises return electrode 260. The position of electrode 155in FIG. 3B is termed herein a “centerline default position”. If thecutting member 145 and electrode 155 were rotated so as to be close toan edge 262 a or 262 b of window 158 in outer sleeve 140, RF currentcould arc between the electrodes 155 and 260 and potentially cause ashort circuit disabling the probe. Therefore, a robust and reliable stopmechanism is required which is described next.

As can be understood from FIGS. 1 and 2A-2B, the controller 165 canalways determine in real time the rotational position of drive coupling150 and therefore the angular or rotational position of the ceramiccutting member 145 and electrode 155 can be determined. A controlleralgorithm can further calculate the rotational angle of the electrode155 away from the centerline default position as the Hall sensor 245 cansense lessening of magnetic field strength as a magnet 255 a or 255 b inthe drive coupling 150 rotates the electrode 155 away from thecenterline default position. Each magnet has a specified, known strengthand the algorithm can use a look-up table with that lists fieldsstrengths corresponding to degrees of rotation away from the defaultposition. Thus, if the Hall signal responsive to the rotated position ofmagnet 255 a or 255 b drops a specified amount from a known peak valuein the centerline default position, it means the electrode 155 has movedaway from the center of the window 158. In one variation, if theelectrode 155 moves a selected rotational angle away from the centerlineposition during RF energy delivery to the electrode, the algorithm turnsoff RF current instantly and alerts the physician by an aural and/orvisual signal, such as an alert on the LCD screen 170 on handpiece 104and/or on a screen on a controller console (not shown). The terminationof RF current delivery thus prevents the potential of an electrical arcbetween electrode 155 and the outer sleeve electrode 260.

It can be understood that during use, when the electrode 155 is in theposition shown in FIG. 3B, the physician may be moving the energizedelectrode over tissue to ablate or coagulate tissue. During such use,the cutting member 145 and electrode 155 can engage or catch on tissuewhich inadvertently rotate the electrode 155 out of the defaultcenterline position. Therefore, the system provides a controlleralgorithm, herein called an “active electrode monitoring” algorithm,wherein the controller continuously monitors position signals generatedby Hall sensor 245 during RF energy delivery in both an ablation modeand a coagulation mode to determine if the electrode 155 and innersleeve 142 have been bumped off the centerline position. In a variation,the controller algorithms can be configured to then re-activate themotor drive 105 to move the inner sleeve 142 and electrode 155 back tothe default centerline position sleeve if electrode 155 had been bumpedoff the centerline position. In another variation, the controlleralgorithms can be configured to again automatically deliver RF currentto RF electrode 155 when it is moved back to the to the defaultcenterline position. Alternatively, the controller 165 can require thephysician to manually re-start the delivery of RF current to the RFelectrode 155 when it is moved back to the to the centerline position.In an aspect of the invention, the drive coupling 150 and thus magnets255 a and 255 b are attached to inner sleeve 142 and cutting member 145in a pre-determined angular relationship relative to longitudinal axis128 so that the Hall sensor generates signals responsive to magnets 255a, 255 b is the same for all probes within a probe type to thus allowthe controller algorithm to function properly.

Now turning to the stop mechanism or algorithms for stopping movement ofa motor-driven component of working end 112, FIG. 8 schematicallyillustrates the algorithm and steps of the stop mechanism. In onevariation, referring to FIG. 8 , the stop mechanism corresponding to theinvention uses (i) a dynamic braking method and algorithm to stop therotation of the inner sleeve 142 and cutting member 145 (FIGS. 1, 3A-3B)in an initial position, and thereafter (ii) a secondary checkingalgorithm is used to check the initial stop position that was attainedwith the dynamic braking algorithm, and if necessary, the stop algorithmcan re-activate the motor drive 105 to slightly reverse (or moveforward) the rotation of drive coupling 150 and inner sleeve 142 asneeded to position the cutting member 145 and electrode 155 within atthe centerline position or within 0° to 5° of the targeted centerlinedefault position. Dynamic braking is described further below. FIG. 8schematically illustrates various aspects of controller algorithms forcontrolling the rotational speed of the cutting member and for stoppingthe cutting member 145 in the default centerline position.

In FIG. 8 , it can be understood that the controller 165 is operatingthe probe 110 of FIGS. 1 and 3A-3B at a “set speed” which may be a PIDcontrolled, continuous rotation mode in one direction or may be anoscillating mode where the motor drive 105 rotates the cutting member145 in one direction and then reverses rotation as is known in the art.At higher rotational speeds such as 1,000 RPM to 20,000 RPM, it is notpractical or feasible to acquire a signal from Hall sensor 245 thatindicates the position of a magnet 255 a or 255 b in the drive coupling150 to apply a stop algorithm. In FIG. 8 , when the physician stopcutting with probe 110 by releasing actuation of an actuator button orfoot pedal, current to the motor drive 105 is turned off. Thereafter,the controller algorithm uses the Hall sensor 245 to monitordeceleration of rotation of the drive coupling 150 and inner sleeve 142until a slower RPM is reached. The deceleration period may be from 10 msto 1 sec and typically is about 100 ms. When a suitable slower RPM isreached which is called a “search speed” herein (see FIG. 8 ), thecontroller 165 re-activates the motor drive 105 to rotate the drivecoupling at a low speed ranging from 10 RPM to 1,000 RPM and in onevariation is between 50 RPM and 250 RPM. An initial “search delay”period ranging from 50 ms to 500 ms is provided to allow the PIDcontroller to stabilize the RPM at the selected search speed.Thereafter, the controller algorithm monitors the Hall position signalof magnet strength and when the magnet parameter reaches a predeterminedthreshold, for example, when the rotational position of drive coupling150 and electrode 155 correspond to the centerline default position ofFIG. 3B, the control algorithm then applies dynamic braking to instantlystop rotation of the motor drive shaft 151, drive coupling 150 and themotor-driven component of the probe. FIG. 8 further illustrates that thecontroller can check the magnet/drive coupling 150 position after thebraking and stopping steps. If the Hall position signal indicates thatthe motor-driven component is out of the targeted default position, themotor drive 105 can be re-activated to move the motor-driven componentand thereafter the brake can be applied again as described above.

Dynamic braking as shown schematically in FIG. 8 may typically stop therotation of the drive coupling 150 with a variance of up to about 0°-15°of the targeted stop position, but this can vary even further whendifferent types of tissue are being cut and impeding rotation of thecutting member 145, and also depending on whether the physician hascompletely disengaged the cutting member from the tissue interface whenthe motor drive is de-activated. Therefore, dynamic braking alone maynot assure that the default or stop position is within a desiredvariance.

As background, the concept of dynamic braking is described in thefollowing literature:https://www.ab.com/support/abdrives/documentation/techpapers/RegenOverview01.pdfandhttp://literature.rockwellautomation.com/idc/groups/literature/documents/wp/drives-wp004-en-p.pdf.Basically, a dynamic braking system provides a chopper transistor on theDC bus of the AC PWM drive that feeds a power resistor that transformsthe regenerative electrical energy into heat energy. The heat energy isdissipated into the local environment. This process is generally calleddynamic braking with the chopper transistor and related control andcomponents called the chopper module and the power resistor called thedynamic brake resistor. The entire assembly of chopper module withdynamic brake resistor is sometimes referred to as the dynamic brakemodule. The dynamic brake resistor allows any magnetic energy stored inthe parasitic inductance of that circuit to be safely dissipated duringthe turn off of the chopper transistor.

The method is called dynamic braking because the amount of brakingtorque that can be applied is dynamically changing as the loaddecelerates. In other words, the braking energy is a function of thekinetic energy in the spinning mass and as it declines, so does thebraking capacity. So the faster it is spinning or the more inertia ithas, the harder you can apply the brakes to it, but as it slows, you runinto the law of diminishing returns and at some point, there is nolonger any braking power left.

In another aspect of the invention, a method has been developed toincrease the accuracy of the stopping mechanism which is a component ofthe positioning algorithm described above. It has been found that eachmagnet in a single-use probe may vary slightly from its specifiedstrength. As described above, the positioning algorithm uses the Halleffect sensor 245 to continuously monitor the field strength of magnets255 a and 255 b as the drive coupling 150 rotates and the algorithmdetermines the rotational position of the magnets and drive couplingbased on the field strength, with the field strength rising and fallingas a magnet rotates past the Hall sensor. Thus, it is important for thealgorithm to have a library of fields strengths that accuratelycorrespond to degrees of rotation away from a peak Hall signal when amagnet is adjacent the sensor 245. For this reason, an initial step ofthe positioning algorithm includes a “learning” step that allow thecontroller to learn the actual field strength of the magnets 255 a and255 b which may vary from the specified strength. After a new single-useprobe 110 (FIG. 1 ) is coupled to the handpiece 104, and after actuationof the motor drive 105, the positioning algorithm will rotate the drivecoupling at least 180° and more often at least 360° while the Hallsensor 245 quantifies the field strength of the particular probe'smagnets 255 a and 255 b. The positioning algorithm then stores themaximum and minimum Hall signals (corresponding to North and Southpoles) and calibrates the library of field strengths that correspond tovarious degrees of rotation away from a Hall min-max signal positionwhen a magnet is adjacent the Hall sensor.

In general, a method of use relating to the learning algorithm comprisesproviding a handpiece with a motor drive, a controller, and a probe witha proximal hub configured for detachable coupling to the handpiece,wherein the motor drive is configured to couple to a rotating drivecoupling in the hub and wherein the drive coupling carries first andsecond magnets with North and South poles positioned differentlyrelative to said axis, and coupling the hub to the handpiece, activatingthe motor drive to thereby rotate the drive coupling and magnets atleast 180°, using a handpiece sensor to sense the strength of eachmagnet, and using the sensed strength of the magnets for calibration ina positioning algorithm that is responsive to the sensor sensing thevarying strength of the magnets in the rotating drive coupling tothereby increase accuracy in calculating the rotational position of thedrive coupling 150.

Another aspect of the invention relates to an enhanced method of useusing a probe working end with an electrode, such as the working end 112of FIGS. 1 and 3B. As described above, a positioning algorithm is usedto stop rotation of the electrode 155 in the default centerline positionof FIG. 3B. An additional “slight oscillation” algorithm is used toactivate the motor drive 105 contemporaneous with RF current to theelectrode 155, particularly an RF cutting waveform for tissues ablation.The slight oscillation thus provides for a form of oscillating RFablation. The slight oscillation algorithm rotates the electrode 155 inone direction to a predetermined degree of rotation, which thecontroller algorithms determine from the Hall position signals. Then,the algorithm reverses direction of the motor drive to rotate in theopposite direction until Hall position signals indicate that thepredetermined degree of rotation was achieved in the opposite directionaway from the electrode's default centerline position. The predetermineddegree of angular motion can be any suitable rotation that is suitablefor dimensions of the outer sleeve window, and in one variation is from1° to 30° in each direction away from the centerline default position.More often, the predetermined degree of angular motion is from 5° to 15°in each direction away from the centerline default. The slightoscillation algorithm can use any suitable PID controlled motor shaftspeed, and in one variation the motor shaft speed is from 50 RPM to5,000 RPM, and more often from 100 RPM to 1,000 RPM. Stated another way,the frequency of oscillation can be from 20 Hz to 2,000 Hz and typicallybetween 40 Hz and 400 Hz.

While the above description of the slight oscillation algorithm isprovided with reference to electrode 155 on a rotating cutting member145 of FIG. 3B, it should be appreciated that a reciprocating electrode212 as shown in the working end 200C of FIG. 6 end could also beactuated with slight oscillation. In other words, the hook shapeelectrode 212 of FIG. 6 could be provided with a frequency ofoscillation ranging from 20 Hz to 2,000 Hz and typically between 40 Hzand 400 Hz.

FIGS. 9A-9B are longitudinal sectional views of a probe hub 120′ thatcorresponds to the working end 200B of FIG. 5 which has a reciprocatingelectrode 210. In FIGS. 9A-9B, the handpiece 104 and Hall affect sensors240 and 245 are of course the same as described above as there is nochange in the handpiece 104 for different types of probes. The probe hub120′ of FIGS. 9A-9B is very similar to the hub 120 of FIGS. 2A-2B withthe first and second identification/orientation magnets 250 a and 250 bbeing the same. The third and fourth rotation al position magnets 255 aand 255 b also are the same and are carried by drive coupling 150′. Theprobe hub 120′ of FIGS. 9A-9B only differs in that the drive coupling150 rotates with a cam mechanism operatively coupled to inner sleeve142′ to convert rotational motion to linear motion to reciprocate theelectrode 210 in working end 200B of FIG. 5 . A similar hub forconverting rotational motion to linear motion is provided for theworking ends 200C and 200D of FIGS. 6 and 7 , respectively, which eachhave a reciprocating component (212, 218) in its working end.

Now turning to FIGS. 10, 11 and 12 , another variation of anarthroscopic shaver or resection probe 400 is shown which somewhatsimilar to that of FIGS. 12 and 3A-3B which comprises a tubular cutterhaving a proximal hub 402 coupled to an elongated shaft assembly 405that extends about central longitudinal axis 406. The shaft assemblycomprises an outer sleeve assembly 410 and a co-axial or concentricinner sleeve assembly 415 that extends to a shaft working end 418. Thehub 402 again is adapted for coupling to a handpiece and motor drivecontrolled by a controller 420A. The controller 420A further controlsthe RF source 420B and negative pressure source 420C as describedpreviously. The controller 420A includes algorithms having the featuresdescribed in previous embodiments for rotating the inner sleeve assembly415 as well as stopping the inner sleeve 415 in a selected rotationalposition, such as a window-closed or window-open position. The workingend 418 again has an outer sleeve resecting window 422 in the outersleeve assembly 410 that cooperates with an inner sleeve resectingwindow 425 (FIG. 12 ) in the inner sleeve assembly 415 for engaging andresecting tissue.

The variation or probe 400 in FIGS. 10, 11 and 12 differs from previousembodiments in that the inner sleeve assembly 415 has a distal endportion 430 that comprises a combination of a longitudinal dielectricmember or body 440 coupled to a longitudinal conductive member orportion 442. The dielectric member 440 can be a ceramic or glassmaterial and the longitudinal conductive portion 442 typically isstainless steel. When assembled, the dielectric member 440 andlongitudinal conductive portion 442 have outer surface that contact oneanother along an interface 444 which is important for reasons describedin more detail below.

As can be seen in FIG. 11 , which shows components of the inner sleeveassembly 415 separated, the longitudinal dielectric member 440 carriesan active electrode 445 which may be also may be referred to as a firstpolarity electrode herein. For convenience, the side of the inner sleeveassembly 415 that carries the electrode 445 is called the electrode sideES and the opposing side which carries inner window 425 is called thewindow side WS. Referring to FIG. 12 , the inner sleeve resecting window425 has circumferentially spaced-apart first and second cutting edges448 a and 448 b that are sharp for mechanically resecting tissue as suchcutting edges 448 a, 448 b shear tissue when rotating or rotationallyoscillating across the cutting edges 450 a and 450 b of the outer sleevewindow 422. Of particular interest, the longitudinal conductive metalportion 442 comprises a return electrode 455 (which also may be termed asecond polarity electrode herein) which cooperates with the firstpolarity or active electrode 445 to deliver energy to tissue. The activeand return electrodes 445 and 455 are operatively coupled to RF source420B and controller 420A as described previously. The outer sleeveassembly 410 has a conductive metal outer tubular member 456 with bore458 therein that extends proximally to the hub 402 and distally to thedistal end portion or housing 459 that carries the outer sleeve window422. The inner sleeve assembly 415 has a co-axial conductive metal innertubular member 460 that extends proximally to the hub 402 and extendsdistally to couple to the assembly of the longitudinal dielectric member440 and the longitudinal metal portion 442. The co-axial metal innertubular member 460 rotates in the bore 458 of the outer tubular member456.

As can be seen best in FIGS. 12 and 14 , the longitudinal metal portion442 has dual functions in that the carries the inner cutting window 425with circumferentially spaced-apart first and second cutting edges 448 aand 448 b and also functions as a return electrode 455 when in awindow-closed position of FIG. 10 , as will be described further below.

Now referring to FIG. 12 , the inner sleeve assembly 415 again is shownseparated from the outer sleeve assembly 410 and is rotated 180° so thatthe electrode side ES faces downward and the window side WS is in anupward position. Thus, it can be seen that the longitudinal metalportion 442 carries the inner resecting window 425. Further, thelongitudinal metal portion 442 extends distally around the tip portion462 of the inner sleeve assembly 415 to thus provide substantial hoopstrength as the tip portion 462 distally surrounds the longitudinaldielectric member 440 on opposing sides of the distal end 464 of thedielectric member 440. As can be seen in FIG. 15 , the proximal end 465of the assembly of the longitudinal dielectric member 440 and thelongitudinal metal portion 442 is dimensioned for insertion into thebore 466 of the thin wall tubular sleeve 460 to complete the structuralcomponents of the inner sleeve assembly 415. Thus, it can be seen howthe tubular sleeve 460 with bore 466 therein slides over and engageswith the longitudinal dielectric member 440 and longitudinal metalportion 442 to provide a strong connection around the proximal end 465of the components. As can best be seen in FIG. 13 , the lateral sides470 a and 470 b of the longitudinal dielectric member 440 are configuredto slide into receiving recesses or grooves 472 a and 472 b on eitherside of the open channel 474 in the longitudinal metal portion 442 tothereby lock the two components 440 and 442 together.

FIG. 14 shows the exploded view of the components of FIG. 13 rotated180° degrees to again show the lateral sides 470 a, 470 b of thedielectric member 440 configured for insertion into the receivinggrooves 472 a, 472 b on either side of the channel 474 in thelongitudinal metal portion 442.

Now turning to FIGS. 13 and 15 , the electrical connections to theactive electrode 445 and return electrodes 455 can be described. In theexploded view of FIG. 13 , it can be seen that an elongated electricallead 475 is adapted to extend longitudinally over the inner tubularmember 460 (FIG. 15 ) to a pad portion 477 that is bendable and adaptedto be inserted into a pad recess 478 in the longitudinal dielectricmember 440. The electrical lead 475 is covered with an insulator (notshown) except for the pad portion 477. As can be easily understood, theactive electrode 445 comprises a metal such as stainless steel, tungstenor any other suitable conductive metal with first and second legs 478 aand 478 b that are adapted for insertion through receiving channels 482a and 482 b in the dielectric member 440 which extend into the padrecess 478. Thus, it can understood that the electrode 445 iscantilevered over a grooved portion 484 of the dielectric member 440distally from the dual receiving channels 482 a and 482 b in thedielectric member 440. The pad 477 of the electrical lead 475 then isplaced in the contact with the legs 478 a and 478 b of the electrode 445and soldered or otherwise electrically coupled in the recess 478.Finally, a potting material (not shown) is used to cover and fill inover the electrical pad 477 and the recess 478. Further, referring toFIG. 15 , it can be seen that tubular member 460 has a flattened surface486 for accommodating the electrical lead 475 as the tubular member 460and bore 466 therein slide over the proximal end 465 of the dielectricmember 440 and metal portion 442. The flattened surface 486 of thetubular member 460 as seen in FIG. 15 allows an insulator layer 488(such as a heat shrink material) shown in phantom view to cover theentirety of the tubular member 460, the insulated electrical lead 475,and the proximal and medial portions 465, 490 of the dielectric member440 and the longitudinal metal portion 442. This describes theelectrical lead 475 extending to the active electrode 445 carried withinthe dielectric member 440. The proximal end (not shown) of theelectrical lead 475 extends into the hub 402 (FIG. 10 ) and thereafterconnects to electrical contacts in a handle which allows for rotation ofthe inner sleeve assembly 415 and for coupling electrical energy to theelectrical lead 475, as described in earlier embodiments.

As described above, the longitudinal metal portion 442 of the innersleeve assembly 415 (FIGS. 13, 15 ) comprises a return electrode 455.However, the inner sleeve assembly 415 does not carry electrical lead tothe longitudinal metal portion 442. Rather, the outer sleeve assembly410 of FIGS. 10, 11 and 12 includes an elongate metal outer tubularmember 456 that comprises an electrical conductor and is adapted tocarry current from the hub 402 to the distal end or housing portion 459of the outer sleeve assembly 410. Since the longitudinal metal portion442 of the inner sleeve assembly 415 rotates with a close fit within thebore 458 of the outer tubular member 456, the longitudinal metal portion442 becomes a return electrode 455 due to its contact with the outertubular member 456. Thus, referring to FIG. 12 , the longitudinal metalconductive portion 442 and the distal end housing 459 of the outertubular member 456 both comprise a return electrode 455.

In another aspect of the invention, referring to FIGS. 15 and 16A, theactive electrode 445 is dome-shaped with a surface 495 that has a radiusor curvature that is a segment of a cylindrical shape so that the outersurface 495 of the dome of the electrode 445 when viewed in a transversesectional view (FIG. 16A) is substantially aligned with the outercylindrical surfaces 496 of the dielectric member 440 and longitudinalmetal portion 442. The dome-shaped surface 495 of the electrode 445 isadvantageous for engaging tissue since it projects outward as opposed toa flat-surface electrode. Further, the thicker, dome-shaped centralportion of electrode 445 results in far slower degradation anddisintegration of the electrode 445 during prolonged use. Such electrodedurability is important for arthroscopic procedures in which theelectrosurgical components of the invention may be used for manyminutes.

Referring again to FIGS. 16A-16B, in one aspect of the invention, thelongitudinal dielectric member 440 together with the longitudinal metalportion 442 form a wall around an interior channel 500 therein thatcommunicates within bore 466 in the inner tubular member 460 and anegative pressure source 420C for aspirating tissue chips and fluid froma working space as is known in the art. In one variation shown in FIGS.16A-16B, the metal wall portion 505 (disregarding the opening of window422 therein) extends radially around axis 406 and the interior channel500 in a radial angle RA1 of at least 90°. Often, the metal wall portion505 will extend radially around the interior channel in a radial angleRA1 of at least 120° or at least 180°. When describing the metal wallportion 505 herein that extends in a radial angle indicated at RA1 inFIGS. 16A-16B, it is meant to refer, for example, to the metal wallportion 505 of FIG. 16B which is a transverse section 16B-16B in FIGS.13-14 which is proximal to window 425, where such a wall portion 505provides the required hoop strength to the metal portion 442. In thisvariation, referring to FIGS. 16A-16B, the wall 510 of the dielectricmember 440 extends radially around the interior channel 500 in a radialangle RA2 of at least 45° or at least 60°. Further, still referring toFIG. 16A, the dome-shaped electrode 445 has a surface 495 that extendsradially around the axis 406 in a radial angle RA3 of at least 5° or atleast 10°.

Now turning to FIG. 17 , another important aspect of the invention canbe described. As can be seen in FIG. 17 , the inner sleeve assembly 415has been stopped in a selected rotational position wherein the electrode445 carried by the dielectric member 440 is positioned centrally in theresecting window 422 of the outer sleeve assembly 410. In thisvariation, it should be appreciated that the outer sleeve window 422 isshown with sharp metal cutting edges without teeth or serrations, but itshould be appreciated that the outer sleeve window 422 can have any formof sharp teeth, serrations or the like and fall within the scope of theinvention.

In FIG. 17 , it can also be seen that the longitudinal metal portion 442of the inner sleeve assembly 415 is exposed in the outer sleeve window422 when the outer sleeve assembly 415 has been stopped in therotational position where electrode 445 is positioned centrally in theresecting window 422. As described above, both the distal portion orhousing 459 of the outer sleeve assembly 410 and the longitudinal metalportion 442 of the inner sleeve assembly 410 comprises return electrodes455. FIG. 17 shows RF current paths CP that indicate the shortest pathfor RF current between the active electrode 445 and the return electrode455 when operating in conductive saline environment. As can be seen inFIG. 17 , the shortest RF current paths CP are from the active electrode445 to the longitudinal metal portion 442 along interface 444 of thedielectric member 440 and metal portion 442 and not the cutting edges450 a and 450 b of the outer window 422 in distal housing 459 whichcomprise the return electrode 455. This aspect of the invention is veryimportant in that the location of the interface 444 between thedielectric member 440 and metal portion 442 is critical to prevent ashort current path CP to the cutting edges 450 a and 450 b of outerwindow 422. If substantial RF current path were directly from electrode445 to cutting edges 450 a and 450 b, the RF plasma at the cutting edgeswould rapidly degrade and dull such edges. In turn, the dull cuttingedges of the outer sleeve window 422 would diminish the resection rateresulting from rotating or oscillating the inner sleeve assembly 415 andwindow 425 in the outer sleeve window 422.

In general, a surgical a probe for resecting tissue corresponding to theinvention (FIGS. 10-17 ) comprises an elongated shaft extending about alongitudinal axis 406 comprising co-axial outer and inner sleeveassemblies 410, 415 having respective outer and inner resecting windows422 and 425 in distal ends thereof, wherein the inner sleeve assemblyhas (i) a longitudinal dielectric wall portion that carries a firstpolarity or active electrode 445, and (ii) a conductive metal wallportion with an inner resecting window 425 with circumferentiallyspaced-apart first and second conductive cutting edges 448 a and 448 bthat comprise a return electrode 455, wherein the active electrode 445is spaced apart from the cutting edges 448 a, 448 b by at least 0.5 mm.An RF source 420B coupled to the active and return electrodes. In othervariations, the first and second polarity electrodes 445, 455 (or activeand return electrodes 445, 455) are spaced apart by at least 1.0 mm orat least 1.5 mm. In a variation, the dielectric member 440 defines alongitudinal interface 444 with a longitudinal edge of an conductivelongitudinal metal portion 442 which comprising a second polarity orreturn electrode.

In general, referring to FIG. 17 , a tissue resecting probecorresponding to the invention comprises an elongated shaft 405extending about a longitudinal axis 406 and further comprises co-axialouter and inner sleeve assemblies 410 and 415 having respective outerand inner resecting windows 433 and 425 in distal ends thereof, whereininner sleeve assembly 415 carries a first polarity electrode 445therein, and both the outer and inner windows 422 and 425 havecircumferentially spaced-apart cutting edges that comprise secondpolarity electrodes.

In another aspect of the invention, again referring FIG. 17 , thesurgical resecting probe comprises a windowed inner sleeve assembly 415rotatable within a windowed outer sleeve assembly 410 wherein acontroller 420A and motor drive are adapted to rotate the inner sleeveassembly through window-open and window-closed positions and wherein thecontroller is adapted to stop motor-driven rotation of the inner sleeveassembly in a selected position wherein the active electrode 445 isspaced apart from cutting edges 450 a and 450 b of the outer sleevewindow 422 and wherein a return electrode 455 is disposed intermediatethe electrode 445 and the cutting edges 450 a and 450 b of the outersleeve window 422.

In another aspect of the invention, referring to FIGS. 13 and 16 , theresecting probe 400 comprises a windowed inner sleeve assembly 415rotatable within a windowed outer sleeve assembly 410 wherein acontroller and motor drive are adapted to rotate the inner sleeveassembly 415 through window-open and window-closed positions, wherein adistal portion of the inner sleeve assembly 415 comprises a cylindricalwall defining an outer surface 496 and an inner surface 498 around aninterior channel 500 therein (FIG. 16B) and wherein the interior channel500 is surrounded in part by a first wall 510 of the longitudinaldielectric member 440 and in part by a second wall 515 of thelongitudinal metal portion 442 and wherein each of the first and secondwalls 510 and 515 comprise substantially the full thickness of thecylindrical wall and is not a thin layer of a composite or layeredassembly. Again, it should be appreciated that the term second wall 515as used herein describes the wall structure proximal to the window 425which is disposed in the longitudinal metal portion 442.

In FIGS. 10-15 , it can be seen that the dielectric member 440 has aport 516 therein that lies under a v-notch 518 in the electrode 445. Theport 516 is adapted for aspiration of fluid therethrough during RFenergy delivery which can reduce bubbles from the vicinity of theelectrode 445 as plasma is formed. Further, FIGS. 10 and 17 show ports520 in the distal end housing 459 of outer sleeve 410 which are adaptedto provide fluid flow through the shaft assembly in a window-closedposition as shown in FIGS. 10 and 17 to maintain a constant fluidoutflow as opposed to a fluctuating outflow as would be the caseotherwise with the inner sleeve assembly 415 rotating at high RPMthrough window-open and window-closed positions.

Now turning to FIGS. 18-19 , another variation of a probe working end525 is shown, and more particularly the distal end of the inner sleeveassembly 415′ is shown in an exploded view and is similar to theembodiment of FIGS. 10 to 16 . The variation of FIG. 18 again includes alongitudinal dielectric body 440′ and a longitudinal conductive metalbody 442′. This variation differs the previous embodiment shown in FIG.13 in that the structure provided for securely coupling the components440′ and 442′ together differs. As can be seen in FIGS. 18 and 19 , thedielectric component 440′ has lateral elements 540 a and 540 b extendingin a part-cylindrical form that are adapted to slide into and engage theinner surfaces 544 of walls 545 of the metal longitudinal metal bodyportion 442′. As best can be seen in FIG. 19 , the lateral elements 540a and 540 b of the dielectric member 440′ have an outer surface 548 witha radius R that matches the inner surface 544 and radius R of the metalportion 442′. Thus, it can be understood that by axially sliding andinserting the dielectric member 440′ can into the longitudinal openingor channel 550 in longitudinal metal portion 442′, a secure and durableconnection can be provided between the dielectric and metal components440′ and 442′. In FIG. 19 , the radial angle RA1 of the metal portion442′ and the radial angle RA2 of the dielectric member 440′ can be thesame as described previously. Additionally, the radial angle RA3 of thesurface of the electrode 445 is the same as described previously.

In FIG. 20 , another variation of a working end 600 of an inner sleeveassembly 615 is provided in an exploded view to illustrate thestructural components that are adapted to securely connect thelongitudinal dielectric member 620 to the longitudinal metal portion622. In this variation, the lateral edges 624 a and 624 b of thedielectric member 620 do not interlock with the lateral edges 628 a and628 b of the metal portion 622 or overlap as in the previous variations.As can be seen in FIGS. 20 and 21 , the interfaces of the lateral edgesof the components 620, 622 simply abut one another and are securelyfixed to one another by a retaining collar 640 that is adapted to fitinto an annular notch or recess 644 in both the dielectric member 620the metal portion 622 to securely hold the components together. As canbe understood, the metal retaining collar 640 can have a discontinuityor gap 648 in its circumference to allow the collar to be tensioned andslipped over the components 620 and 622 into the recess 644. Thereafter,the gap 648 in the collar 640 can be welded to thus permanently couplethe dielectric and metal components 620 and 622.

In the variation shown in FIG. 20 , it can be seen that an activeelectrode 650 with legs 652 a and 652 b is similar to the versiondescribed previously in FIGS. 13-15 . In FIG. 20 , it can be seen thatthe legs 652 a and 652 b extend into receiving channels 654 a and 654 bin the dielectric member 620. The electrical lead 660 in FIG. 20 againhas a pad element 662 that is received by a recess 664 in the dielectricmember 620 to contact electrical leads 665 therein. In this variation,the electrical leads 655 in the recess 664 are bare to make electricalcontact with the pad element 662 but are coated with an insulator 668 isthe location where such leads extend through the dielectric member 620and into contact with the legs 652 a and 652 b of the electrode 650. Inall other respects, the assembly of components in FIG. 20 functions inthe same manner as described previously. In FIG. 21 , it can be seenthat the radial angles RA1, RA2 of the walls of the metal member 622 anddielectric member 620 can be the same as described previously.Additionally, the radial angle RA3 of the surface of the electrode 650is the same as described previously.

Now turning to FIGS. 22-26 , another variation of probe 700 is shownwith hub 702 and shaft 705 (see FIG. 25A) extending about longitudinalaxis 706 to a working end 708 shown in FIG. 22 . FIG. 22 shows a distalportion of the outer sleeve assembly 710 and bore 712 therein togetherwith inner sleeve assembly 715. FIG. 23 shows the inner sleeve assembly715 from a different angle to better illustrate the electrical lead 718carried by the inner sleeve. Now turning to FIG. 24 which is an explodedview of the inner sleeve assembly 715, it can be seen that thelongitudinal dielectric member 720 is again secured to the longitudinalmetal portion 722 and coupled to tubular member 724 with a retainingcollar 725. Such a retaining collar 725 used to fix together thedielectric member 720 and the metal portion 722 can be similar to thatdescribed in the embodiment of FIG. 20 .

Referring to FIG. 24 , this variation differs from previous embodimentsin that the electrical lead 718 extends through a recess 730 in thedielectric member 720 and couples to a leg 732 of the active electrode735. The electrical lead 718 is not carried on an exterior surface oftubular member 724. Instead, the electrical lead 718 extends to theactive electrode 735 through the interior bore 742 of the tubularmember. As can be seen in FIG. 22 , the electrical lead 718 extends inthe proximal direction from the electrode 735 and is flexed at bend 744to enter the interior bore 742 of the inner tubular member 724 and inthis variation extends through a hypotube 745 which is coupled to thewall of the tubular member 740. It can be seen that a slot 748 isprovided in the wall of and tubular member 724 which allows for weldingthe hypotube 745 to the interior surface of bore 742 in the tubularmember 724. At least one similar slot (not shown) can be provided alongthe length of the tubular member 724 to secure the hypotube 745 inplace. It has been found that is important to carry the electrical lead718 within the interior bore 742 of the tubular member 724 to protect itfrom potential damage. In the previous embodiments, for example theversion of FIG. 15 , the electrical lead 475 extended in a flat surface486 along the outer surface of the inner tubular member 460 and was thencovered with insulator layer 488. In the previous embodiment of FIG. 15, since the shaft 405 of the probe 400 (FIG. 10 ) could be torqued andbent significantly during a procedure, high-speed rotation of the innersleeve assembly 415 had the potential of abrading and degrading theinsulator sleeve 488 overlying the electrical lead 425 which could causean electrical short. Therefore, one aspect of the invention as shown inFIGS. 22-24 includes carrying the electrical lead 718 in the interiorbore 742 of the metal tubular member 724 to insure that bending ortorque on the shaft 705 while operating the inner sleeve assembly 715 athigh RPM cannot damage the electrical lead 718. FIGS. 22 and 24 alsoshow an annular bushing 746 that is adapted to cover the recess 730 thatis filled with potting material as described previously. Referring againto FIG. 22 , a heat shrink insulator sleeve 748 covering the tubularmember 724 and the at least a portion of the bushing 746. Thus, in highspeed rotation, the insulator sleeve 749 and bushing 746 are the bearingsurfaces of the inner sleeve assembly 715 as it rotates in the outersleeve 710.

It can be appreciated from FIGS. 22-24 that the inner tubular member 724and the hypotube 745 comprise a return electrode 750 with conductivesaline flowing through the interior channel 755 of the tubular member724. Thus, obviously the electrical lead 718 carries its own substantialinsulation layer on it surface. In one variation, the electrical lead718 is a copper wire instead of a stainless steel wire since such astainless steel wire would be resistively heated. Preferably, theelectrical lead 718 is of a material that will not be resistively heatedas this would heat saline outflows traveling through the channel 755which would then elevate the temperature of the handpiece which isundesirable.

Now turning to FIGS. 25A and 25B, a perspective view and a cut-away viewof the hub 702 are shown. FIG. 26 is an enlarged cut-away view of aninterior portion of the hub 702. As can be seen in FIGS. 25B and 26 ,the hypotube 745 carries the electrical lead 718 that extends throughthe inner tubular member 724. As can be seen in FIG. 25B, the tubularmember 724 extends through the hub 702 and the hypotube 745 has aproximal end 758 in the interior of the hub. The proximal end portion760 of the electrical lead 718 is curved outwardly through a slot 762 inthe tubular member 724 and then extends in an interface 765 between twopolymer collars 766 and 768 that together provide a seal over and aroundthe insulation layer on the electrical lead 718. Thereafter, a heatshrink material 769 such as FEP can disposed over the collars 766 and768 (FIG. 26 ). In FIGS. 25B and 26 , it can be seen that a polymericcoupling sleeve 770 is fixed to the proximal end portion 772 of thetubular member that extends proximally to the drive coupler 774 which isadapted for coupling to the motor drive of the handpiece (not shown).FIGS. 25B and 26 further show conductive metal contact ring 775 isdisposed over the insulative coupling sleeve 770. As can be seen in FIG.26 , on the proximal side of the contact ring 775, another polymericcollar 776 is shown that again is covered with an FEP or other heatshrink material. Still referring to FIG. 26 , the proximalmost end 777of electrical lead 718 with its insulator layer removed is in contactwith and electrically coupled to the rotating contact ring 775. In turn,the contact ring 775 interfaces with spring-loaded ball contacts 780 aand 780 b in the handpiece (not shown) to carry RF current to from RFsource 720B to the active electrode 735 (FIG. 22 ). Spring-loaded ballcontacts 782 a and 782 b in the hub are adapted to carry current to orfrom the outer sleeve assembly 710 which comprises a return electrode.It should be appreciated that conductive fluid can migrate into variousparts of the hub 702 and it is necessary to prevent any migration ofconductive fluid into the interface between the spring-loaded ballcontacts 780 a and 780 b and the rotating contact ring 775. Anymigrating conductive fluid is effectively a return electrode and couldcause a short circuit. To insure that there is no migration conductivefluid into contact with contact ring 775, FIGS. 25B and 26 illustrate aflexible seal 785 that has is flexible annular sealing elements 788 aand 788 b that are both proximal and distal from the rotating contactring 775. By the means, the chamber 790 in which the spring-loaded ballcontacts 780 a and 780 b engage the contact ring 775 will remainfluid-tight.

Now turning to FIGS. 27-30 , another variation of an arthroscopic tool800 is shown which again has a proximal hub 802 coupled to an elongatedshaft assembly 805 that extends about central longitudinal axis 806. Theshaft assembly 805 includes an outer sleeve assembly 810 having acentral passage extending from a proximal end to a distal end thereofand an inner sleeve assembly 815 having a central passage extending froma proximal end to a distal end thereof. The inner sleeve assembly 815extends to a working end 818 and is sized and configured to be rotatablyreceived in the inner passage of the outer sleeve assembly 810. The hub802 again is adapted for coupling to a handpiece and motor drivecontrolled by a controller 420A, RF source 420B and negative pressuresource 420C as described previously. The controller 420A again includesalgorithms for rotating the inner sleeve assembly 815 at selected RPMsas well as for stopping the inner sleeve 815 in a selected rotationalposition relative to the outer sleeve 810.

In this variation, referring to FIG. 28 , the outer sleeve 810 has adistal opening 820 with a scoop configuration or spoon shape with spoonportion 822 extending under a rotating burr 825 carried at the workingend 818 of the inner sleeve assembly 815. The burr 825 is adapted forcutting hard tissue with a plurality of cutting edges 830 that can rangein number from 2 to 20, wherein the burr 825 often has from 2 to 8cutting edges.

The burr 825 of FIGS. 27-29 has some characteristics in common with thedistal end portion 430 of the inner sleeve assembly 415 of FIGS. 10-15 ,wherein the burr 825 comprises a combination of a longitudinaldielectric member or body 840 coupled to a longitudinal conductive metalmember 842 that carries the sharp burr edges 830. The dielectric member840 can be a ceramic or glass material and the longitudinal conductivemember 842 typically is stainless steel. When assembled, the dielectricmember 840 and longitudinal conductive member 842 have outer surfacesthat contact one another along interface 844 which is described in moredetail below.

Now referring to FIGS. 28, 29 and 31 , the longitudinal dielectricmember 840 carries an active electrode 845, which may be termed a firstpolarity electrode herein. For convenience, the side of the burr 825that carries electrode 845 is called the electrode side ES and theopposing side configured with sharp cutting edges is called the cuttingside CS.

As can be best understood from FIGS. 27, 28, and 30 , a return electrode855 (which may be termed a second polarity electrode herein) is formedas part of the outer sleeve 810 which cooperates with the first polarityor active electrode 845 to deliver energy to tissue. The active andreturn electrodes 845 and 855 are operatively coupled to RF source 420Band controller 420A as described above.

Referring to FIG. 28 , the outer sleeve 810 comprises a conductive metalsuch as stainless steel with bore 856 therein that extends proximally tothe hub 802 and distally to the distal end opening 820 and spoon portion822 (FIGS. 28 and 30 ). The inner sleeve assembly 815 comprises aco-axial conductive metal inner tubular member 860 that extendsproximally to hub 802 and extends distally to couple to the burr 825which consists of the longitudinal dielectric member 840 and thelongitudinal metal member 842. The metal inner tubular sleeve 860rotates in bore 856 of the outer sleeve 810.

Now turning to FIG. 31 , the inner sleeve assembly 815 is shown inexploded view separated from outer sleeve 810 with the electrode side ESfacing upward and the cutting side CS facing downward. In FIG. 30 , itcan be seen that the longitudinal metal member 842 comprises a body thatcircumferentially extends greater than 180° around axis 806 and interiorpassageway 865 such that the metal member 842 provides the burr 825 withsufficient strength for cutting hard tissue at high RPMs with cuttingedges 830 extending longitudinally over the length of the burr 825 anddistally around distal tip 868 thereof. As can be understood, thelongitudinal dielectric member 840 is thus protected from high stresseson the burr edges 830 when cutting hard tissue such as bone at highRPMs. In this variation, the lateral edges 872 a and 872 b of thedielectric member 840 do not interlock with the lateral edges 874 a and874 b of the metal member 842 or overlap as in the previous variations.As can be seen in FIGS. 28 and 29 , the interfaces of the lateral edgesof the components 840 and 842 abut one another and are securely fixedtogether by a retaining collar 875 that fits tightly over reduceddiameter annular portion 877 of the dielectric member 840 the metalmember 842 to securely hold the components together. Again, the metalretaining collar 875 has a discontinuity 878 in its circumference toallow the collar to be tensioned and slipped over the components 840 and842 and then welded.

Referring to FIGS. 29-31 , the proximal end 880 of the longitudinalmetal member 842 is dimensioned for insertion into the bore 882 of athin wall tubular sleeve 860 to form the structural components of theinner sleeve assembly 815. It can be seen how the tubular sleeve 860with bore 882 therein slides over and engages the reduced diameterannular portion 877 of the metal member 842 to provide a durableconnection. FIG. 29 shows the assembly of the tubular sleeve 860, thedielectric member 840 and metal member 842 without first and secondcircumferential bushings 890 and 892 as can be seen in FIGS. 28 and 30which will be described further below.

Now turning to FIGS. 29-31 , the electrical connections to the activeelectrode 845 and return electrode 855 are described. In the explodedview of FIG. 31 , it can be seen that electrical lead 895 extendslongitudinally over a slightly flattened surface 896 of sleeve 860 andan inwardly bent tab 898 of the tubular member 860. The electrical lead895 is covered with an insulator (not shown) except for its distal end899. Referring to FIG. 31 , the active electrode 845 again is configuredwith first and second legs 902 a and 902 b that are adapted forinsertion through receiving channels 904 a and 904 b in the dielectricmember 840. Thus, the electrode 845 again is cantilevered over a recess910 in the dielectric member 840 distally from the dual receivingchannels 904 a and 904 b in the dielectric member 840. The distal end899 of the electrical lead 895 is then soldered or otherwiseelectrically coupled to a leg 902 a or 902 b of the electrode 845.

The flattened surface 896 of the tubular member 860 as shown in FIGS.29-30 allows an insulator layer 912 such as a heat shrink material shownin FIGS. 28 and 30 to cover the entirety of the tubular member 860 andthe insulated electrical lead 895. The proximal end (not shown) of theelectrical lead 895 extends into a hub 802 (cf. FIG. 10 ) as describedpreviously to connect to electrical contacts in a handle which allowsfor rotation of the inner sleeve assembly 815 and for couplingelectrical energy to the electrical lead 895.

Now turning to FIGS. 28, 30 and 31 , it can be seen that the first andsecond circumferential bushings 890 and 892 are fixed around a distalportion of the rotating inner sleeve 815 when fully assembled. Theproximal bushing 890 comprises a metal material which adds additionalstrength to the connection between the inner sleeve 885 and the distalburr 825. Further, the proximal or first bushing 890 is adapted torotate within the bore 856 of the outer sleeve 810 with closetolerances. The second or distal bushing 892 comprises a polymermaterial such as PEEK which is adapted to rotate at high speeds withinthe bore 856 of outer sleeve 810 and prevents any metal-on-metal contactin the exposed distal end of the probe to thereby insure that no metalmicroparticles are being formed in or about the exposed end of probeduring high-speed rotation of the inner sleeve assembly 815 in the outersleeve 810.

Referring to FIGS. 28 and 30 , it can be seen that a distal region ofouter sleeve 810 is configured with a plurality of apertures oraspiration ports 915 therein (FIG. 28 ) that are circumferentiallyspaced apart and proximal from the distal end opening 820 of the outersleeve 810. These ports 915 can range in number from 1 to 10 and areadapted for suctioning fluid and debris from a fluid-filled working siteduring use. In FIG. 30 , it can be seen that the proximal bushing 890,inner sleeve 860 and metal cutting member 842 provide a lateral opening920 in the inner sleeve assembly 815 that communicates with the interiorchannel 865 of metal member 842 and bore 882 of the inner sleeve 860which further communicates with the negative pressure source 420C. Thus,during rotation of the inner sleeve assembly 815, it can be understoodthat the opening 920 in the inner sleeve assembly 815 will rotate tointermittently interface with the ports 915 in outer sleeve 810 tothereby suction fluid from the working space. Further, it can beappreciated that the stop mechanism controlled by the controller 420Acan be adapted to stop rotation of inner sleeve assembly 815 in aparticular rotational position, for example, with the electrode side ESfacing upwardly as in FIG. 30 . In this position, the ports 915 in theouter sleeve 810 are not aligned with the opening 920 in the innersleeve so that aspiration forces in the interior bore 882 of the innersleeve 860 will suction fluid through the port 922 in dielectric member840 beneath the electrode 845 similar to that described previously. Inthis variation, the aspiration forces through the port 922 can beeffective in removing bubbles from the vicinity of the electrode 845during operation.

In other variations, the outer sleeve ports 915 may be configured foralignment with the inner sleeve opening 920 when the inner sleeveassembly 815 is stopped with the electrode side ES facing in an upwardposition as in FIG. 30 . Depending on the use of the device, it may bedesirable to have the ports 915 and opening 920 aligned or partlyaligned to assist in removing ablated tissue debris from a treatmentsite during activation of the electrode 845 and/or to maintain acontinuous fluid flow through the probe in any stopped position of theinner sleeve assembly 815.

In general, it can be understood that the devices of the inventiondescribed above are adapted to function in two different operationalmodes. First, the working end of the probe 800 of FIG. 27 utilizeshigh-speed rotation of the inner sleeve assembly 815 to cut and removetissue. Second, the controller 420A can stop rotation of the innersleeve assembly 815 so that the active electrode 845 is exposed andthereafter the electrode can be energized to coagulate or ablate tissue,depending on wave form and power delivered.

In another aspect of the invention, a third mode of operation isprovided and consists of contemporaneous rotation of the inner sleeveassembly 815 together with activation of the active electrode 845. Thismode of operation can thereby cut and remove tissue at the same time ascoagulating or ablating tissue with RF energy. In this third mode ofoperation, it is necessary to sequence the activation of RF energy tothe active electrode 845 during each 360° rotation of the inner sleeveassembly 815 so that the active electrode 845, effectively, does notform a short circuit with the return electrode 855 of the outer sleeve810. In one variation, micro switches can be provided in the proximalhub of the probe to turn RF energy delivery on and off during eachrotation of the inner sleeve assembly. However, such micro switches orother similar encoding mechanisms may that operate instantaneously andeffectively during high-speed rotation.

Now turning to FIGS. 32-33 , electronic circuitry 940 is shown that isconfigured to instantly turn RF delivery ON and OFF during each 360°rotation of the inner sleeve assembly 815 relative to the outer sleeve810 in the probe 800 of FIGS. 27-31 . The circuitry 940 also can be usedall other probe variations described above. The controller 420A and RFsource 420B (FIGS. 10 and 27 ) are designed to prevent the possibilityof RF current flowing from the active electrode 545 carried by an innersleeve directly to an outer sleeve which comprises return electrode 855herein when the active and return electrodes 845, 855 are in contact orin close proximity to one another. The circuit 940 that accomplishes theinstantaneous ON/OFF switching is shown in FIG. 32 . The circuit 940 isbuilt around the current sense transformer T1, comparator U2 and gatedriver U1. The RF current flowing from the electrode 845 to a nearbyelectrode or otherwise conductive material in a saline working space ismeasured using T1. The current is rectified by rectifier D 1 and sent tothe comparator U2 where it is compared against a reference voltage thatdefines an RF output disable threshold. When the rectified voltageexceeds the threshold on the comparator, the comparator output goesdown, bringing down the enable input of the gate driver U1, whichreduces the RF current by disabling the RF output. Hysteresis in thecomparator is shown in FIG. 33 and is implemented using positivefeedback through R1 and C1. This hysteresis prevents oscillation aroundthe threshold created by the reference voltage. The RF current mustsignificantly decrease below the threshold for the RF to be re-enabled.By this means, the disable/enable of RF output can occur extremelyrapidly, which is set by the time constant of the RC filter in front ofthe comparator. In one variation, such a time constant is 2.26 ms andthe scope of the invention includes such a time constant of less than 10ms, or less than 5 ms. The RF output can turn ON/OFF practicallyinstantly as the comparator is controlling the enable input of the gatedrivers that drive the RF output MOSFETs. The gate driver enable delayis 75 nS (max) and can be as much as ten thousand times faster than thecomparator time constant or 2 ms.

The circuit 940 described above thus allows controlled RF currentdelivery contemporaneous with high-speed rotation of an inner sleeveassembly 815 at rotational speed of at least 5000 RPM, at least 10,000RPM, at least 12,000 RPM and at least 15,000 RPM. The circuit 940 ofFIGS. 32 and 33 can be used with any of the cutting probes describedabove in FIGS. 10-26 and the burr 800 shown in FIGS. 27 to 31 .

Although particular embodiments of the present invention have beendescribed above in detail, it will be understood that this descriptionis merely for purposes of illustration and the above description of theinvention is not exhaustive. Specific features of the invention areshown in some drawings and not in others, and this is for convenienceonly and any feature may be combined with another in accordance with theinvention. A number of variations and alternatives will be apparent toone having ordinary skills in the art. Such alternatives and variationsare intended to be included within the scope of the claims. Particularfeatures that are presented in dependent claims can be combined and fallwithin the scope of the invention. The invention also encompassesembodiments as if dependent claims were alternatively written in amultiple dependent claim format with reference to other independentclaims.

Other variations are within the spirit of the present invention. Thus,while the invention is susceptible to various modifications andalternative constructions, certain illustrated embodiments thereof areshown in the drawings and have been described above in detail. It shouldbe understood, however, that there is no intention to limit theinvention to the specific form or forms disclosed, but on the contrary,the intention is to cover all modifications, alternative constructions,and equivalents falling within the spirit and scope of the invention, asdefined in the appended claims.

The use of the terms “a” and “an” and “the” and similar referents in thecontext of describing the invention (especially in the context of thefollowing claims) are to be construed to cover both the singular and theplural, unless otherwise indicated herein or clearly contradicted bycontext. The terms “comprising,” “having,” “including,” and “containing”are to be construed as open-ended terms (i.e., meaning “including, butnot limited to,”) unless otherwise noted. The term “connected” is to beconstrued as partly or wholly contained within, attached to, or joinedtogether, even if there is something intervening. Recitation of rangesof values herein are merely intended to serve as a shorthand method ofreferring individually to each separate value falling within the range,unless otherwise indicated herein, and each separate value isincorporated into the specification as if it were individually recitedherein. All methods described herein can be performed in any suitableorder unless otherwise indicated herein or otherwise clearlycontradicted by context. The use of any and all examples, or exemplarylanguage (e.g., “such as”) provided herein, is intended merely to betterilluminate embodiments of the invention and does not pose a limitationon the scope of the invention unless otherwise claimed. No language inthe specification should be construed as indicating any non-claimedelement as essential to the practice of the invention.

Preferred embodiments of this invention are described herein, includingthe best mode known to the inventors for carrying out the invention.Variations of those preferred embodiments may become apparent to thoseof ordinary skill in the art upon reading the foregoing description. Theinventors expect skilled artisans to employ such variations asappropriate, and the inventors intend for the invention to be practicedotherwise than as specifically described herein. Accordingly, thisinvention includes all modifications and equivalents of the subjectmatter recited in the claims appended hereto as permitted by applicablelaw. Moreover, any combination of the above-described elements in allpossible variations thereof is encompassed by the invention unlessotherwise indicated herein or otherwise clearly contradicted by context.

All references, including publications, patent applications, andpatents, cited herein are hereby incorporated by reference to the sameextent as if each reference were individually and specifically indicatedto be incorporated by reference and were set forth in its entiretyherein.

1. A tissue cutting probe comprising: an outer sleeve assembly having aproximal end, a distal end, and central passage extending therebetween;an inner sleeve assembly coaxially and rotatably received in the centralpassage of the outer sleeve assembly and having a proximal end, a distalend, and central passage extending therebetween; a burr having aplurality of metal cutting edges carried a first side of the distal endof the inner sleeve assembly; and an electrode carried a second side ofthe distal end of the inner sleeve assembly.
 2. A tissue cutting probeas in claim 1, wherein the first side and the second side are on opposedsurfaces of the inner sleeve assembly.
 3. A tissue cutting probe as inclaim 2, wherein the burr is formed on a metal member that extends atleast 180° circumferentially about the distal end of the inner sleeveassembly.
 4. A tissue cutting probe as in claim 2, wherein the electrodeis carried on a dielectric body on the distal end of the inner sleeveassembly.
 5. A tissue cutting probe as in claim 1, wherein a scoopextends distally from the distal end of the outer sleeve assembly.
 6. Atissue cutting probe as in claim 5, wherein the scoop is axially alignedwith the burr and the electrode on the inner sleeve assembly so that thescoop will alternatively cover each of the burr and the electrode as theinner sleeve assembly is rotated within the outer sleeve assembly.
 7. Atissue cutting probe as in claim 1, wherein one or more aspiration portsare formed in a wall of the outer sleeve assembly and one or morelateral openings are formed in a wall of the inner sleeve assembly, saidone or more aspiration ports positioned to align with the one or morelateral openings as the inner sleeve assembly is rotated within theouter sleeve assembly.
 8. A tissue cutting system comprising: (a) aprobe having an elongated shaft extending about a longitudinal axis withan inner sleeve assembly that is rotatable at greater than 1000 RPMwithin the outer sleeve assembly; an active electrode on a distal end ofthe inner sleeve assembly; and a return electrode on a distal end of theouter sleeve; and (b) a controller configured to deliver radiofrequency(RF) current to the active and return electrodes and to limit RF currentdelivery when the active electrode is proximate the return electrodeduring rotation of the inner sleeve assembly.
 9. A tissue cutting systemas in claim 8, wherein the controller senses the current or voltageflowing to the active electrode and compares a sensed value to areference value and disables the current flow when the sensed valueexceeds the reference value.
 10. A tissue cutting system as in claim 9,wherein current flow is enabled when the sensed value falls below thereference value.
 11. A tissue cutting system as in claim 10, whereincurrent flow is enabled or disabled only if the reference value isexceeded or fallen below by a threshold value to prevent oscillation.12. A method for cutting tissue, said method comprising: engaging adistal end of a probe against a tissue target; rotating a distal end ofa sleeve assembly, wherein the distal end carries (a) a burr having aplurality of metal cutting edges on a first side thereof and anelectrode on a second side thereof; and selectively applyingradiofrequency current to the electrode and a return electrode as thesleeve assembly is rotated, wherein current flow is enable when theelectrode is remote from the return electrode and wherein current flowis disabled when the electrode is proximate the return electrode as thesleeve assembly is rotated.
 13. (canceled)
 14. A method as in claim 12,wherein selectively applying current comprises sensing a current orvoltage flowing to the active electrode and comparing a sensed value toa reference value, wherein the current flow is disabled when the sensedvalue exceeds the reference value.
 15. A tissue cutting system as inclaim 14, wherein current flow is enabled when the sensed value fallsbelow the reference value.
 16. A tissue cutting system as in claim 15,wherein current flow is enabled or disabled only if the reference valueis exceeded or fallen below by a threshold value to prevent oscillation.17. (canceled)
 18. (canceled)
 19. A method as in claim 12, wherein thefirst side and the second side are on opposed surfaces of the innersleeve assembly.
 20. A method as in claim 19, wherein the burr is formedon a metal member that extends at least 180° circumferentially about thedistal end of the inner sleeve assembly.
 21. A method as in claim 19,wherein the electrode is carried on a dielectric body on the distal endof the inner sleeve assembly.
 22. A method as in claim 12, wherein ascoop extends distally from the distal end of the outer sleeve assembly.23. A method as in claim 22, wherein the scoop is axially aligned withthe burr and the electrode on the inner sleeve assembly so that thescoop will alternatively cover each of the burr and the electrode as theinner sleeve assembly is rotated within the outer sleeve assembly.